This invention relates to the reprocessing of reclaimed vulcanized rubber into a thermoplastic substrate.
Notwithstanding the tremendous amount of waste and scrap vulcanized rubber, such as tires, flashings and trimmings, no acceptable proposal has been advanced to convert such waste products into renewed products which are of a high quality and are reusable or reprocessable. It is known to use ground rubber as a filler in an elastomeric thermoset, but the product has only one useful life and are not easily recycled. Thermosets have an additional disadvantage of requiring a curing cycle in a heated mold, although the articles produced are generally less expensive than comparable thermoplastic articles.
It is also known to incorporate reclaimed rubber buffings or particles as fillers into thermoplastic resins and rubbers. Thermoplastics have the advantage that they can be reclaimed by remelting and are easier to process into a final form. Addition of reclaimed rubber in particulate form at reasonably high levels, however, causes undesirable loss of properties in the article, since the rubber particles are usually not compatible with the thermoplastic phase, either because the particle size is too large, or the particles do not bind well in the system. Finer rubber grinds can be employed, but only at a significant increase in cost.